In the manufacture of corrugated paper cartons or boxes, rectangular corrugated sheets or blanks are first produced in a machine known as a corrugator. The sheets are then stacked for storage and handling purposes. They are subsequently individually processed through a printer or a die cutter that either imprints each sheet or forms carton blanks machine to the requirements of a customer.
Printing machines and die cutters operate at very high rates of speed. Simply loading successive vertical stacks of the corrugated sheets into an infeed hopper for such a machine is ineffective because of the amount of physical labor required to place each stack accurately within the hopper. The amount of labor required would result in an interruption of the operation of the machinery being fed or running the machine at a reduced rate of speed.
The present machine and method assure that a continuous supply or corrugated sheets is maintained within the infeed hopper of a printing machine or a die cutting machine while operating at a high rate of speed. This is accomplished by unstacking the corrugated sheets and pre-feeding them to the receiving hopper of the sheet processing machinery in a continuous shingled manner at a delivery rate that will not interrupt operation of the sheet processing machinery.
Where the incoming sheets or blanks are handled in very large stacks, it has been found advisable to design machines that initially divide each stack into a plurality of smaller "blocks" which are then successively handled and shingled along a longitudinal path leading to the blank processing machinery being fed. After being divided, each block might be inverted or simply deposited on a feed conveyor leading to a shingle gate.
The division of a large stack of corrugated sheets or blanks into several equally-sized blocks requires accurate squaring and alignment of the side edges of each block after it has been divided from the stack and deposited on the receiving end of a moving conveyor. Such side alignment is critical to the subsequent shingling and pre-feeding operations.
Because a pre-feeding machine must meet infeed requirements of a variety of downstream machines, versatile alignment capabilities are required.
The present disclosure utilizes a novel movable support assembly for laterally movable squaring shoes. Each shoe can be adjustably connected to opposed flights of a chain to square and align the block edges along a centerline on the machine or off-center from the centerline, as well as along a side edge of the block.